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                        <h1 id="promise%E5%AF%B9%E8%B1%A1">Promise&#x5BF9;&#x8C61;</h1>
<h2 id="%E5%9F%BA%E6%9C%AC%E7%94%A8%E6%B3%95">&#x57FA;&#x672C;&#x7528;&#x6CD5;</h2>
<p>ES6&#x539F;&#x751F;&#x63D0;&#x4F9B;&#x4E86;Promise&#x5BF9;&#x8C61;&#x3002;&#x6240;&#x8C13;Promise&#x5BF9;&#x8C61;&#xFF0C;&#x5C31;&#x662F;&#x4EE3;&#x8868;&#x4E86;&#x672A;&#x6765;&#x67D0;&#x4E2A;&#x5C06;&#x8981;&#x53D1;&#x751F;&#x7684;&#x4E8B;&#x4EF6;&#xFF08;&#x901A;&#x5E38;&#x662F;&#x4E00;&#x4E2A;&#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#xFF09;&#x3002;&#x5B83;&#x7684;&#x597D;&#x5904;&#x5728;&#x4E8E;&#xFF0C;&#x6709;&#x4E86;Promise&#x5BF9;&#x8C61;&#xFF0C;&#x5C31;&#x53EF;&#x4EE5;&#x5C06;&#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#x4EE5;&#x540C;&#x6B65;&#x64CD;&#x4F5C;&#x7684;&#x6D41;&#x7A0B;&#x8868;&#x8FBE;&#x51FA;&#x6765;&#xFF0C;&#x907F;&#x514D;&#x4E86;&#x5C42;&#x5C42;&#x5D4C;&#x5957;&#x7684;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x3002;&#x6B64;&#x5916;&#xFF0C;Promise&#x5BF9;&#x8C61;&#x8FD8;&#x63D0;&#x4F9B;&#x4E86;&#x4E00;&#x6574;&#x5957;&#x5B8C;&#x6574;&#x7684;&#x63A5;&#x53E3;&#xFF0C;&#x4F7F;&#x5F97;&#x53EF;&#x4EE5;&#x66F4;&#x52A0;&#x5BB9;&#x6613;&#x5730;&#x63A7;&#x5236;&#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#x3002;Promise&#x5BF9;&#x8C61;&#x7684;&#x6982;&#x5FF5;&#x7684;&#x8BE6;&#x7EC6;&#x89E3;&#x91CA;&#xFF0C;&#x8BF7;&#x53C2;&#x8003;<a href="javascript:;" target="_blank">&#x300A;JavaScript&#x6807;&#x51C6;&#x53C2;&#x8003;&#x6559;&#x7A0B;&#x300B;</a>&#x3002;</p>
<p>ES6&#x7684;Promise&#x5BF9;&#x8C61;&#x662F;&#x4E00;&#x4E2A;&#x6784;&#x9020;&#x51FD;&#x6570;&#xFF0C;&#x7528;&#x6765;&#x751F;&#x6210;Promise&#x5B9E;&#x4F8B;&#x3002;&#x4E0B;&#x9762;&#x662F;Promise&#x5BF9;&#x8C61;&#x7684;&#x57FA;&#x672C;&#x7528;&#x6CD5;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-keyword">var</span> promise = <span class="hljs-keyword">new</span> <span class="hljs-built_in">Promise</span>(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">resolve, reject</span>) </span>{
  <span class="hljs-keyword">if</span> (<span class="hljs-comment">/* &#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#x6210;&#x529F; */</span>){
    resolve(value);
  } <span class="hljs-keyword">else</span> {
    reject(error);
  }
});

promise.then(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">value</span>) </span>{
  <span class="hljs-comment">// success</span>
}, <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">value</span>) </span>{
  <span class="hljs-comment">// failure</span>
});
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x8868;&#x793A;&#xFF0C;Promise&#x6784;&#x9020;&#x51FD;&#x6570;&#x63A5;&#x53D7;&#x4E00;&#x4E2A;&#x51FD;&#x6570;&#x4F5C;&#x4E3A;&#x53C2;&#x6570;&#xFF0C;&#x8BE5;&#x51FD;&#x6570;&#x7684;&#x4E24;&#x4E2A;&#x53C2;&#x6570;&#x5206;&#x522B;&#x662F;resolve&#x65B9;&#x6CD5;&#x548C;reject&#x65B9;&#x6CD5;&#x3002;&#x5982;&#x679C;&#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#x6210;&#x529F;&#xFF0C;&#x5219;&#x7528;resolve&#x65B9;&#x6CD5;&#x5C06;Promise&#x5BF9;&#x8C61;&#x7684;&#x72B6;&#x6001;&#x53D8;&#x4E3A;&#x201C;&#x6210;&#x529F;&#x201D;&#xFF08;&#x5373;&#x4ECE;pending&#x53D8;&#x4E3A;resolved&#xFF09;&#xFF1B;&#x5982;&#x679C;&#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#x5931;&#x8D25;&#xFF0C;&#x5219;&#x7528;reject&#x65B9;&#x6CD5;&#x5C06;&#x72B6;&#x6001;&#x53D8;&#x4E3A;&#x201C;&#x5931;&#x8D25;&#x201D;&#xFF08;&#x5373;&#x4ECE;pending&#x53D8;&#x4E3A;rejected&#xFF09;&#x3002;</p>
<p>promise&#x5B9E;&#x4F8B;&#x751F;&#x6210;&#x4EE5;&#x540E;&#xFF0C;&#x53EF;&#x4EE5;&#x7528;then&#x65B9;&#x6CD5;&#x5206;&#x522B;&#x6307;&#x5B9A;resolve&#x65B9;&#x6CD5;&#x548C;reject&#x65B9;&#x6CD5;&#x7684;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x3002;</p>
<p>&#x4E0B;&#x9762;&#x662F;&#x4E00;&#x4E2A;&#x4F7F;&#x7528;Promise&#x5BF9;&#x8C61;&#x7684;&#x7B80;&#x5355;&#x4F8B;&#x5B50;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">timeout</span>(<span class="hljs-params">ms</span>) </span>{
  <span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> <span class="hljs-built_in">Promise</span>((resolve) =&gt; {
    setTimeout(resolve, ms);
  });
}

timeout(<span class="hljs-number">100</span>).then(() =&gt; {
  <span class="hljs-built_in">console</span>.log(<span class="hljs-string">&apos;done&apos;</span>);
});
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x7684;timeout&#x65B9;&#x6CD5;&#x8FD4;&#x56DE;&#x4E00;&#x4E2A;Promise&#x5B9E;&#x4F8B;&#x5BF9;&#x8C61;&#xFF0C;&#x8868;&#x793A;&#x4E00;&#x6BB5;&#x65F6;&#x95F4;&#x4EE5;&#x540E;&#x6539;&#x53D8;&#x81EA;&#x8EAB;&#x72B6;&#x6001;&#xFF0C;&#x4ECE;&#x800C;&#x89E6;&#x53D1;then&#x65B9;&#x6CD5;&#x7ED1;&#x5B9A;&#x7684;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x3002;</p>
<p>&#x4E0B;&#x9762;&#x662F;&#x4E00;&#x4E2A;&#x7528;Promise&#x5BF9;&#x8C61;&#x5B9E;&#x73B0;&#x7684;Ajax&#x64CD;&#x4F5C;&#x7684;&#x4F8B;&#x5B50;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-keyword">var</span> getJSON = <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">url</span>) </span>{
  <span class="hljs-keyword">var</span> promise = <span class="hljs-keyword">new</span> <span class="hljs-built_in">Promise</span>(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">resolve, reject</span>)</span>{
    <span class="hljs-keyword">var</span> client = <span class="hljs-keyword">new</span> XMLHttpRequest();
    client.open(<span class="hljs-string">&quot;GET&quot;</span>, url);
    client.onreadystatechange = handler;
    client.responseType = <span class="hljs-string">&quot;json&quot;</span>;
    client.setRequestHeader(<span class="hljs-string">&quot;Accept&quot;</span>, <span class="hljs-string">&quot;application/json&quot;</span>);
    client.send();

    <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">handler</span>(<span class="hljs-params"></span>) </span>{
      <span class="hljs-keyword">if</span> (<span class="hljs-keyword">this</span>.status === <span class="hljs-number">200</span>) { 
              resolve(<span class="hljs-keyword">this</span>.response); 
          } <span class="hljs-keyword">else</span> { 
              reject(<span class="hljs-keyword">new</span> <span class="hljs-built_in">Error</span>(<span class="hljs-keyword">this</span>.statusText)); 
          }
    };
  });

  <span class="hljs-keyword">return</span> promise;
};

getJSON(<span class="hljs-string">&quot;/posts.json&quot;</span>).then(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">json</span>) </span>{
  <span class="hljs-built_in">console</span>.log(<span class="hljs-string">&apos;Contents: &apos;</span> + json);
}, <span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">error</span>) </span>{
  <span class="hljs-built_in">console</span>.error(<span class="hljs-string">&apos;&#x51FA;&#x9519;&#x4E86;&apos;</span>, error);
});
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x4E2D;&#xFF0C;resolve&#x65B9;&#x6CD5;&#x548C;reject&#x65B9;&#x6CD5;&#x8C03;&#x7528;&#x65F6;&#xFF0C;&#x90FD;&#x5E26;&#x6709;&#x53C2;&#x6570;&#x3002;&#x5B83;&#x4EEC;&#x7684;&#x53C2;&#x6570;&#x4F1A;&#x88AB;&#x4F20;&#x9012;&#x7ED9;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x3002;reject&#x65B9;&#x6CD5;&#x7684;&#x53C2;&#x6570;&#x901A;&#x5E38;&#x662F;Error&#x5BF9;&#x8C61;&#x7684;&#x5B9E;&#x4F8B;&#xFF0C;&#x800C;resolve&#x65B9;&#x6CD5;&#x7684;&#x53C2;&#x6570;&#x9664;&#x4E86;&#x6B63;&#x5E38;&#x7684;&#x503C;&#x4EE5;&#x5916;&#xFF0C;&#x8FD8;&#x53EF;&#x80FD;&#x662F;&#x53E6;&#x4E00;&#x4E2A;Promise&#x5B9E;&#x4F8B;&#xFF0C;&#x6BD4;&#x5982;&#x50CF;&#x4E0B;&#x9762;&#x8FD9;&#x6837;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-keyword">var</span> p1 = <span class="hljs-keyword">new</span> <span class="hljs-built_in">Promise</span>(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">resolve, reject</span>)</span>{
  <span class="hljs-comment">// ... some code</span>
});

<span class="hljs-keyword">var</span> p2 = <span class="hljs-keyword">new</span> <span class="hljs-built_in">Promise</span>(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">resolve, reject</span>)</span>{
  <span class="hljs-comment">// ... some code</span>
  resolve(p1);
})
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x4E2D;&#xFF0C;p1&#x548C;p2&#x90FD;&#x662F;Promise&#x7684;&#x5B9E;&#x4F8B;&#xFF0C;&#x4F46;&#x662F;p2&#x7684;resolve&#x65B9;&#x6CD5;&#x5C06;p1&#x4F5C;&#x4E3A;&#x53C2;&#x6570;&#xFF0C;&#x8FD9;&#x65F6;p1&#x7684;&#x72B6;&#x6001;&#x5C31;&#x4F1A;&#x4F20;&#x9012;&#x7ED9;p2&#x3002;&#x5982;&#x679C;&#x8C03;&#x7528;&#x7684;&#x65F6;&#x5019;&#xFF0C;p1&#x7684;&#x72B6;&#x6001;&#x662F;pending&#xFF0C;&#x90A3;&#x4E48;p2&#x7684;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x5C31;&#x4F1A;&#x7B49;&#x5F85;p1&#x7684;&#x72B6;&#x6001;&#x6539;&#x53D8;&#xFF1B;&#x5982;&#x679C;p1&#x7684;&#x72B6;&#x6001;&#x5DF2;&#x7ECF;&#x662F;fulfilled&#x6216;&#x8005;rejected&#xFF0C;&#x90A3;&#x4E48;p2&#x7684;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x5C06;&#x4F1A;&#x7ACB;&#x523B;&#x6267;&#x884C;&#x3002;</p>
<h2 id="promise-prototype-then%E6%96%B9%E6%B3%95%EF%BC%9A%E9%93%BE%E5%BC%8F%E6%93%8D%E4%BD%9C">Promise.prototype.then&#x65B9;&#x6CD5;&#xFF1A;&#x94FE;&#x5F0F;&#x64CD;&#x4F5C;</h2>
<p>Promise.prototype.then&#x65B9;&#x6CD5;&#x8FD4;&#x56DE;&#x7684;&#x662F;&#x4E00;&#x4E2A;&#x65B0;&#x7684;Promise&#x5BF9;&#x8C61;&#xFF0C;&#x56E0;&#x6B64;&#x53EF;&#x4EE5;&#x91C7;&#x7528;&#x94FE;&#x5F0F;&#x5199;&#x6CD5;&#x3002;</p>
<pre><code class="lang-javascript">
getJSON(<span class="hljs-string">&quot;/posts.json&quot;</span>).then(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">json</span>) </span>{
  <span class="hljs-keyword">return</span> json.post;
}).then(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">post</span>) </span>{
  <span class="hljs-comment">// proceed</span>
});
</code></pre>
<p>&#x4E0A;&#x9762;&#x7684;&#x4EE3;&#x7801;&#x4F7F;&#x7528;then&#x65B9;&#x6CD5;&#xFF0C;&#x4F9D;&#x6B21;&#x6307;&#x5B9A;&#x4E86;&#x4E24;&#x4E2A;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x3002;&#x7B2C;&#x4E00;&#x4E2A;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x5B8C;&#x6210;&#x4EE5;&#x540E;&#xFF0C;&#x4F1A;&#x5C06;&#x8FD4;&#x56DE;&#x7ED3;&#x679C;&#x4F5C;&#x4E3A;&#x53C2;&#x6570;&#xFF0C;&#x4F20;&#x5165;&#x7B2C;&#x4E8C;&#x4E2A;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x3002;</p>
<p>&#x5982;&#x679C;&#x524D;&#x4E00;&#x4E2A;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x8FD4;&#x56DE;&#x7684;&#x662F;Promise&#x5BF9;&#x8C61;&#xFF0C;&#x8FD9;&#x65F6;&#x540E;&#x4E00;&#x4E2A;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x5C31;&#x4F1A;&#x7B49;&#x5F85;&#x8BE5;Promise&#x5BF9;&#x8C61;&#x6709;&#x4E86;&#x8FD0;&#x884C;&#x7ED3;&#x679C;&#xFF0C;&#x624D;&#x4F1A;&#x8FDB;&#x4E00;&#x6B65;&#x8C03;&#x7528;&#x3002;</p>
<pre><code class="lang-javascript">
getJSON(<span class="hljs-string">&quot;/post/1.json&quot;</span>).then(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">post</span>) </span>{
  <span class="hljs-keyword">return</span> getJSON(post.commentURL);
}).then(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">comments</span>) </span>{
  <span class="hljs-comment">// &#x5BF9;comments&#x8FDB;&#x884C;&#x5904;&#x7406;</span>
});
</code></pre>
<p>&#x8FD9;&#x79CD;&#x8BBE;&#x8BA1;&#x4F7F;&#x5F97;&#x5D4C;&#x5957;&#x7684;&#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#xFF0C;&#x53EF;&#x4EE5;&#x88AB;&#x5F88;&#x5BB9;&#x6613;&#x5F97;&#x6539;&#x5199;&#xFF0C;&#x4ECE;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x7684;&#x201C;&#x6A2A;&#x5411;&#x53D1;&#x5C55;&#x201D;&#x6539;&#x4E3A;&#x201C;&#x5411;&#x4E0B;&#x53D1;&#x5C55;&#x201D;&#x3002;</p>
<h2 id="promise-prototype-catch%E6%96%B9%E6%B3%95%EF%BC%9A%E6%8D%95%E6%8D%89%E9%94%99%E8%AF%AF">Promise.prototype.catch&#x65B9;&#x6CD5;&#xFF1A;&#x6355;&#x6349;&#x9519;&#x8BEF;</h2>
<p>Promise.prototype.catch&#x65B9;&#x6CD5;&#x662F;Promise.prototype.then(null, rejection)&#x7684;&#x522B;&#x540D;&#xFF0C;&#x7528;&#x4E8E;&#x6307;&#x5B9A;&#x53D1;&#x751F;&#x9519;&#x8BEF;&#x65F6;&#x7684;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x3002;</p>
<pre><code class="lang-javascript">
getJSON(<span class="hljs-string">&quot;/posts.json&quot;</span>).then(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">posts</span>) </span>{
  <span class="hljs-comment">// some code</span>
}).catch(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">error</span>) </span>{
  <span class="hljs-comment">// &#x5904;&#x7406;&#x524D;&#x4E00;&#x4E2A;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x8FD0;&#x884C;&#x65F6;&#x53D1;&#x751F;&#x7684;&#x9519;&#x8BEF;</span>
  <span class="hljs-built_in">console</span>.log(<span class="hljs-string">&apos;&#x53D1;&#x751F;&#x9519;&#x8BEF;&#xFF01;&apos;</span>, error);
});
</code></pre>
<p>Promise&#x5BF9;&#x8C61;&#x7684;&#x9519;&#x8BEF;&#x5177;&#x6709;&#x201C;&#x5192;&#x6CE1;&#x201D;&#x6027;&#x8D28;&#xFF0C;&#x4F1A;&#x4E00;&#x76F4;&#x5411;&#x540E;&#x4F20;&#x9012;&#xFF0C;&#x76F4;&#x5230;&#x88AB;&#x6355;&#x83B7;&#x4E3A;&#x6B62;&#x3002;&#x4E5F;&#x5C31;&#x662F;&#x8BF4;&#xFF0C;&#x9519;&#x8BEF;&#x603B;&#x662F;&#x4F1A;&#x88AB;&#x4E0B;&#x4E00;&#x4E2A;catch&#x8BED;&#x53E5;&#x6355;&#x83B7;&#x3002;</p>
<pre><code class="lang-javascript">
getJSON(<span class="hljs-string">&quot;/post/1.json&quot;</span>).then(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">post</span>) </span>{
  <span class="hljs-keyword">return</span> getJSON(post.commentURL);
}).then(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">comments</span>) </span>{
  <span class="hljs-comment">// some code</span>
}).catch(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">error</span>) </span>{
  <span class="hljs-comment">// &#x5904;&#x7406;&#x524D;&#x4E24;&#x4E2A;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x7684;&#x9519;&#x8BEF;</span>
});
</code></pre>
<h2 id="promise-all%E6%96%B9%E6%B3%95%EF%BC%8Cpromise-race%E6%96%B9%E6%B3%95">Promise.all&#x65B9;&#x6CD5;&#xFF0C;Promise.race&#x65B9;&#x6CD5;</h2>
<p>Promise.all&#x65B9;&#x6CD5;&#x7528;&#x4E8E;&#x5C06;&#x591A;&#x4E2A;Promise&#x5B9E;&#x4F8B;&#xFF0C;&#x5305;&#x88C5;&#x6210;&#x4E00;&#x4E2A;&#x65B0;&#x7684;Promise&#x5B9E;&#x4F8B;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-keyword">var</span> p = <span class="hljs-built_in">Promise</span>.all([p1,p2,p3]);
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x4E2D;&#xFF0C;Promise.all&#x65B9;&#x6CD5;&#x63A5;&#x53D7;&#x4E00;&#x4E2A;&#x6570;&#x7EC4;&#x4F5C;&#x4E3A;&#x53C2;&#x6570;&#xFF0C;p1&#x3001;p2&#x3001;p3&#x90FD;&#x662F;Promise&#x5BF9;&#x8C61;&#x7684;&#x5B9E;&#x4F8B;&#x3002;&#xFF08;Promise.all&#x65B9;&#x6CD5;&#x7684;&#x53C2;&#x6570;&#x4E0D;&#x4E00;&#x5B9A;&#x662F;&#x6570;&#x7EC4;&#xFF0C;&#x4F46;&#x662F;&#x5FC5;&#x987B;&#x5177;&#x6709;iterator&#x63A5;&#x53E3;&#xFF0C;&#x4E14;&#x8FD4;&#x56DE;&#x7684;&#x6BCF;&#x4E2A;&#x6210;&#x5458;&#x90FD;&#x662F;Promise&#x5B9E;&#x4F8B;&#x3002;&#xFF09;</p>
<p>p&#x7684;&#x72B6;&#x6001;&#x7531;p1&#x3001;p2&#x3001;p3&#x51B3;&#x5B9A;&#xFF0C;&#x5206;&#x6210;&#x4E24;&#x79CD;&#x60C5;&#x51B5;&#x3002;</p>
<p>&#xFF08;1&#xFF09;&#x53EA;&#x6709;p1&#x3001;p2&#x3001;p3&#x7684;&#x72B6;&#x6001;&#x90FD;&#x53D8;&#x6210;fulfilled&#xFF0C;p&#x7684;&#x72B6;&#x6001;&#x624D;&#x4F1A;&#x53D8;&#x6210;fulfilled&#xFF0C;&#x6B64;&#x65F6;p1&#x3001;p2&#x3001;p3&#x7684;&#x8FD4;&#x56DE;&#x503C;&#x7EC4;&#x6210;&#x4E00;&#x4E2A;&#x6570;&#x7EC4;&#xFF0C;&#x4F20;&#x9012;&#x7ED9;p&#x7684;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x3002;</p>
<p>&#xFF08;2&#xFF09;&#x53EA;&#x8981;p1&#x3001;p2&#x3001;p3&#x4E4B;&#x4E2D;&#x6709;&#x4E00;&#x4E2A;&#x88AB;rejected&#xFF0C;p&#x7684;&#x72B6;&#x6001;&#x5C31;&#x53D8;&#x6210;rejected&#xFF0C;&#x6B64;&#x65F6;&#x7B2C;&#x4E00;&#x4E2A;&#x88AB;reject&#x7684;&#x5B9E;&#x4F8B;&#x7684;&#x8FD4;&#x56DE;&#x503C;&#xFF0C;&#x4F1A;&#x4F20;&#x9012;&#x7ED9;p&#x7684;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x3002;</p>
<p>&#x4E0B;&#x9762;&#x662F;&#x4E00;&#x4E2A;&#x5177;&#x4F53;&#x7684;&#x4F8B;&#x5B50;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-comment">// &#x751F;&#x6210;&#x4E00;&#x4E2A;Promise&#x5BF9;&#x8C61;&#x7684;&#x6570;&#x7EC4;</span>
<span class="hljs-keyword">var</span> promises = [<span class="hljs-number">2</span>, <span class="hljs-number">3</span>, <span class="hljs-number">5</span>, <span class="hljs-number">7</span>, <span class="hljs-number">11</span>, <span class="hljs-number">13</span>].map(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">id</span>)</span>{
  <span class="hljs-keyword">return</span> getJSON(<span class="hljs-string">&quot;/post/&quot;</span> + id + <span class="hljs-string">&quot;.json&quot;</span>);
});

<span class="hljs-built_in">Promise</span>.all(promises).then(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">posts</span>) </span>{
  <span class="hljs-comment">// ...  </span>
}).catch(<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">reason</span>)</span>{
  <span class="hljs-comment">// ...</span>
});
</code></pre>
<p>Promise.race&#x65B9;&#x6CD5;&#x540C;&#x6837;&#x662F;&#x5C06;&#x591A;&#x4E2A;Promise&#x5B9E;&#x4F8B;&#xFF0C;&#x5305;&#x88C5;&#x6210;&#x4E00;&#x4E2A;&#x65B0;&#x7684;Promise&#x5B9E;&#x4F8B;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-keyword">var</span> p = <span class="hljs-built_in">Promise</span>.race([p1,p2,p3]);
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x4E2D;&#xFF0C;&#x53EA;&#x8981;p1&#x3001;p2&#x3001;p3&#x4E4B;&#x4E2D;&#x6709;&#x4E00;&#x4E2A;&#x5B9E;&#x4F8B;&#x7387;&#x5148;&#x6539;&#x53D8;&#x72B6;&#x6001;&#xFF0C;p&#x7684;&#x72B6;&#x6001;&#x5C31;&#x8DDF;&#x7740;&#x6539;&#x53D8;&#x3002;&#x90A3;&#x4E2A;&#x7387;&#x5148;&#x6539;&#x53D8;&#x7684;Promise&#x5B9E;&#x4F8B;&#x7684;&#x8FD4;&#x56DE;&#x503C;&#xFF0C;&#x5C31;&#x4F20;&#x9012;&#x7ED9;p&#x7684;&#x8FD4;&#x56DE;&#x503C;&#x3002;</p>
<p>&#x5982;&#x679C;Promise.all&#x65B9;&#x6CD5;&#x548C;Promise.race&#x65B9;&#x6CD5;&#x7684;&#x53C2;&#x6570;&#xFF0C;&#x4E0D;&#x662F;Promise&#x5B9E;&#x4F8B;&#xFF0C;&#x5C31;&#x4F1A;&#x5148;&#x8C03;&#x7528;&#x4E0B;&#x9762;&#x8BB2;&#x5230;&#x7684;Promise.resolve&#x65B9;&#x6CD5;&#xFF0C;&#x5C06;&#x53C2;&#x6570;&#x8F6C;&#x4E3A;Promise&#x5B9E;&#x4F8B;&#xFF0C;&#x518D;&#x8FDB;&#x4E00;&#x6B65;&#x5904;&#x7406;&#x3002;</p>
<h2 id="promise-resolve%E6%96%B9%E6%B3%95%EF%BC%8Cpromise-reject%E6%96%B9%E6%B3%95">Promise.resolve&#x65B9;&#x6CD5;&#xFF0C;Promise.reject&#x65B9;&#x6CD5;</h2>
<p>&#x6709;&#x65F6;&#x9700;&#x8981;&#x5C06;&#x73B0;&#x6709;&#x5BF9;&#x8C61;&#x8F6C;&#x4E3A;Promise&#x5BF9;&#x8C61;&#xFF0C;Promise.resolve&#x65B9;&#x6CD5;&#x5C31;&#x8D77;&#x5230;&#x8FD9;&#x4E2A;&#x4F5C;&#x7528;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-keyword">var</span> jsPromise = <span class="hljs-built_in">Promise</span>.resolve($.ajax(<span class="hljs-string">&apos;/whatever.json&apos;</span>));
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x5C06;jQuery&#x751F;&#x6210;deferred&#x5BF9;&#x8C61;&#xFF0C;&#x8F6C;&#x4E3A;&#x4E00;&#x4E2A;&#x65B0;&#x7684;ES6&#x7684;Promise&#x5BF9;&#x8C61;&#x3002;</p>
<p>&#x5982;&#x679C;Promise.resolve&#x65B9;&#x6CD5;&#x7684;&#x53C2;&#x6570;&#xFF0C;&#x4E0D;&#x662F;&#x5177;&#x6709;then&#x65B9;&#x6CD5;&#x7684;&#x5BF9;&#x8C61;&#xFF08;&#x53C8;&#x79F0;thenable&#x5BF9;&#x8C61;&#xFF09;&#xFF0C;&#x5219;&#x8FD4;&#x56DE;&#x4E00;&#x4E2A;&#x65B0;&#x7684;Promise&#x5BF9;&#x8C61;&#xFF0C;&#x4E14;&#x5B83;&#x7684;&#x72B6;&#x6001;&#x4E3A;fulfilled&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-keyword">var</span> p = <span class="hljs-built_in">Promise</span>.resolve(<span class="hljs-string">&apos;Hello&apos;</span>);

p.then(<span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params">s</span>)</span>{
  <span class="hljs-built_in">console</span>.log(s)
});
<span class="hljs-comment">// Hello</span>
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x751F;&#x6210;&#x4E00;&#x4E2A;&#x65B0;&#x7684;Promise&#x5BF9;&#x8C61;&#x7684;&#x5B9E;&#x4F8B;p&#xFF0C;&#x5B83;&#x7684;&#x72B6;&#x6001;&#x4E3A;fulfilled&#xFF0C;&#x6240;&#x4EE5;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x4F1A;&#x7ACB;&#x5373;&#x6267;&#x884C;&#xFF0C;Promise.resolve&#x65B9;&#x6CD5;&#x7684;&#x53C2;&#x6570;&#x5C31;&#x662F;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x7684;&#x53C2;&#x6570;&#x3002;</p>
<p>&#x5982;&#x679C;Promise.resolve&#x65B9;&#x6CD5;&#x7684;&#x53C2;&#x6570;&#x662F;&#x4E00;&#x4E2A;Promise&#x5BF9;&#x8C61;&#x7684;&#x5B9E;&#x4F8B;&#xFF0C;&#x5219;&#x4F1A;&#x88AB;&#x539F;&#x5C01;&#x4E0D;&#x52A8;&#x5730;&#x8FD4;&#x56DE;&#x3002;</p>
<p>Promise.reject(reason)&#x65B9;&#x6CD5;&#x4E5F;&#x4F1A;&#x8FD4;&#x56DE;&#x4E00;&#x4E2A;&#x65B0;&#x7684;Promise&#x5B9E;&#x4F8B;&#xFF0C;&#x8BE5;&#x5B9E;&#x4F8B;&#x7684;&#x72B6;&#x6001;&#x4E3A;rejected&#x3002;Promise.reject&#x65B9;&#x6CD5;&#x7684;&#x53C2;&#x6570;reason&#xFF0C;&#x4F1A;&#x88AB;&#x4F20;&#x9012;&#x7ED9;&#x5B9E;&#x4F8B;&#x7684;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-keyword">var</span> p = <span class="hljs-built_in">Promise</span>.reject(<span class="hljs-string">&apos;&#x51FA;&#x9519;&#x4E86;&apos;</span>);

p.then(<span class="hljs-literal">null</span>, <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params">s</span>)</span>{
  <span class="hljs-built_in">console</span>.log(s)
});
<span class="hljs-comment">// &#x51FA;&#x9519;&#x4E86;</span>
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x751F;&#x6210;&#x4E00;&#x4E2A;Promise&#x5BF9;&#x8C61;&#x7684;&#x5B9E;&#x4F8B;p&#xFF0C;&#x72B6;&#x6001;&#x4E3A;rejected&#xFF0C;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x4F1A;&#x7ACB;&#x5373;&#x6267;&#x884C;&#x3002;</p>
<h2 id="async%E5%87%BD%E6%95%B0">async&#x51FD;&#x6570;</h2>
<p>async&#x51FD;&#x6570;&#x662F;&#x7528;&#x6765;&#x53D6;&#x4EE3;&#x56DE;&#x8C03;&#x51FD;&#x6570;&#x7684;&#x53E6;&#x4E00;&#x79CD;&#x65B9;&#x6CD5;&#x3002;</p>
<p>&#x53EA;&#x8981;&#x51FD;&#x6570;&#x540D;&#x4E4B;&#x524D;&#x52A0;&#x4E0A;async&#x5173;&#x952E;&#x5B57;&#xFF0C;&#x5C31;&#x8868;&#x660E;&#x8BE5;&#x51FD;&#x6570;&#x5185;&#x90E8;&#x6709;&#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#x3002;&#x8BE5;&#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#x5E94;&#x8BE5;&#x8FD4;&#x56DE;&#x4E00;&#x4E2A;Promise&#x5BF9;&#x8C61;&#xFF0C;&#x524D;&#x9762;&#x7528;await&#x5173;&#x952E;&#x5B57;&#x6CE8;&#x660E;&#x3002;&#x5F53;&#x51FD;&#x6570;&#x6267;&#x884C;&#x7684;&#x65F6;&#x5019;&#xFF0C;&#x4E00;&#x65E6;&#x9047;&#x5230;await&#x5C31;&#x4F1A;&#x5148;&#x8FD4;&#x56DE;&#xFF0C;&#x7B49;&#x5230;&#x89E6;&#x53D1;&#x7684;&#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#x5B8C;&#x6210;&#xFF0C;&#x518D;&#x63A5;&#x7740;&#x6267;&#x884C;&#x51FD;&#x6570;&#x4F53;&#x5185;&#x540E;&#x9762;&#x7684;&#x8BED;&#x53E5;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-keyword">async</span> <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">getStockPrice</span>(<span class="hljs-params">symbol, currency</span>) </span>{
    <span class="hljs-keyword">let</span> price = <span class="hljs-keyword">await</span> getStockPrice(symbol);
    <span class="hljs-keyword">return</span> convert(price, currency);
}
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x662F;&#x4E00;&#x4E2A;&#x83B7;&#x53D6;&#x80A1;&#x7968;&#x62A5;&#x4EF7;&#x7684;&#x51FD;&#x6570;&#xFF0C;&#x51FD;&#x6570;&#x524D;&#x9762;&#x7684;async&#x5173;&#x952E;&#x5B57;&#xFF0C;&#x8868;&#x660E;&#x8BE5;&#x51FD;&#x6570;&#x5C06;&#x8FD4;&#x56DE;&#x4E00;&#x4E2A;Promise&#x5BF9;&#x8C61;&#x3002;&#x8C03;&#x7528;&#x8BE5;&#x51FD;&#x6570;&#x65F6;&#xFF0C;&#x5F53;&#x9047;&#x5230;await&#x5173;&#x952E;&#x5B57;&#xFF0C;&#x7ACB;&#x5373;&#x8FD4;&#x56DE;&#x5B83;&#x540E;&#x9762;&#x7684;&#x8868;&#x8FBE;&#x5F0F;&#xFF08;getStockPrice&#x51FD;&#x6570;&#xFF09;&#x4EA7;&#x751F;&#x7684;Promise&#x5BF9;&#x8C61;&#xFF0C;&#x4E0D;&#x518D;&#x6267;&#x884C;&#x51FD;&#x6570;&#x4F53;&#x5185;&#x540E;&#x9762;&#x7684;&#x8BED;&#x53E5;&#x3002;&#x7B49;&#x5230;getStockPrice&#x5B8C;&#x6210;&#xFF0C;&#x518D;&#x81EA;&#x52A8;&#x56DE;&#x5230;&#x51FD;&#x6570;&#x4F53;&#x5185;&#xFF0C;&#x6267;&#x884C;&#x5269;&#x4E0B;&#x7684;&#x8BED;&#x53E5;&#x3002;</p>
<p>&#x4E0B;&#x9762;&#x662F;&#x4E00;&#x4E2A;&#x66F4;&#x4E00;&#x822C;&#x6027;&#x7684;&#x4F8B;&#x5B50;&#x3002;</p>
<pre><code class="lang-javascript">
<span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">timeout</span>(<span class="hljs-params">ms</span>) </span>{
  <span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> <span class="hljs-built_in">Promise</span>((resolve) =&gt; {
    setTimeout(resolve, ms);
  });
}

<span class="hljs-keyword">async</span> <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">asyncValue</span>(<span class="hljs-params">value</span>) </span>{
  <span class="hljs-keyword">await</span> timeout(<span class="hljs-number">50</span>);
  <span class="hljs-keyword">return</span> value;
}
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x4E2D;&#xFF0C;asyncValue&#x51FD;&#x6570;&#x524D;&#x9762;&#x6709;async&#x5173;&#x952E;&#x5B57;&#xFF0C;&#x8868;&#x660E;&#x51FD;&#x6570;&#x4F53;&#x5185;&#x6709;&#x5F02;&#x6B65;&#x64CD;&#x4F5C;&#x3002;&#x6267;&#x884C;&#x7684;&#x65F6;&#x5019;&#xFF0C;&#x9047;&#x5230;await&#x8BED;&#x53E5;&#x5C31;&#x4F1A;&#x5148;&#x8FD4;&#x56DE;&#xFF0C;&#x7B49;&#x5230;timeout&#x51FD;&#x6570;&#x6267;&#x884C;&#x5B8C;&#x6BD5;&#xFF0C;&#x518D;&#x8FD4;&#x56DE;value&#x3002;</p>
<p>async&#x51FD;&#x6570;&#x5E76;&#x4E0D;&#x5C5E;&#x4E8E;ES6&#xFF0C;&#x800C;&#x662F;&#x88AB;&#x5217;&#x5165;&#x4E86;ES7&#xFF0C;&#x4F46;&#x662F;traceur&#x7F16;&#x8BD1;&#x5668;&#x5DF2;&#x7ECF;&#x5B9E;&#x73B0;&#x4E86;&#x8FD9;&#x4E2A;&#x529F;&#x80FD;&#x3002;</p>

                    
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